The present invention relates generally to equipment for making up and breaking out threaded members and more specifically to a drilling rig kelly spinner for making up or breaking a joint of pipe in an oil well drilling operation.
In many situations it is necessary to make up, thread together, or break out, unthread, members together. In some commercial applications this process is required on a very frequent basis requiring significant time. For example, during the process of drilling well bores it is continuously required to connect joints of pipe together. This process of making and breaking joints of pipe is time consuming and therefore an expensive process. The process of making and breaking threaded connections is very dangerous and often results in injury to the operators, very commonly known as roughnecks.
A kelly spinner is a well known tool for making up (and breaking out when necessary) a joint of pipe by application of a fixed amount of torque. Use of a kelly spinner can significantly reduce the time required for the joint makeup operation and the potential of spark formation and lost fingers in comparison to spinning chains used for many years.
Kelly spinners typically comprise a geared stem having suitable pipe connections at each end. The stem is installed in the string between a derrick swivel and a kelly joint. A motor then turns the stem which in turn spins the kelly joint to makeup a new joint on the end of the kelly opposite from the kelly spinner.
Spinning chains have primarily been replaced with pneumatic kelly spinners in recent years. The current type pneumatic kelly spinners utilize a vane type air motor and operate at a single, wide open, speed. This type motor requires a surge of air to start it""s rotation and must maintain a certain speed to continue rotating. Thus, these prior art kelly spinners can only be operated at full speed (approximately 150 to 200 rpm, depending on the load, when making up or breaking out pipe). This single speed operation of the kelly spinner is a safety hazard, resulting in immediate high speed spinning of the pipe. Which may cause kicking of the pipe or kelly injuring the roughnecks. Additionally, this wide open operation of the prior art kelly spinners increases the wobble in the stem and results in a shorten life of the kelly spinner and damages the other threaded joints within the string. It is a benefit therefore to provide a multi-speed kelly spinner to increase worker safety and increase the operating life of the kelly spinner and the other associated connections within the string.
Another drawback of these prior art, vane type, air motor kelly spinners is the excessive use of pressurized air. Typically, on a drilling rig or at a drilling site, various equipment and numerous tools are pneumatically operated and or controlled. However, due to space limitations and production costs, pressurized air is very often limited at the well site. Therefore, it is desired to limit air flow requirements wherever possible. The prior art type kelly spinners consume approximately 600 standard cubic feet per minute (scfm) at 120 psi to produce 25 horsepower and 93 foot-pounds torque. It is a benefit therefore to provide a variable speed kelly spinner that requires less air flow for operation then the prior kelly spinners.
The current art vane type kelly spinners require a dry, lubricated source of pressurized air for operation. Thus, the prior art kelly spinners require a lubricator and water trap for proper operation. These requirements add to the expense and unreliability of the system. It is therefore an additional benefit to provide a kelly spinner that can operate with a lower quality air source than the prior art kelly spinners.
It is therefore a benefit to provide a kelly spinner having variable operational speeds, increasing safety in the operation of the kelly spinner and reducing wear on the kelly spinner and associated threaded couplings. It is a further benefit to provide a kelly spinner that requires less air flow for operation than the prior art kelly spinners. It is a still further benefit to provide a kelly spinner that reduces the need for lubricators and water traps in the pneumatic system for operation of the kelly spinner. It is a still further benefit to provide a kelly spinner having a bearing system that increases the longevity of the kelly spinner and reduces wear on the associated equipment.
It is thus an object of the invention to provide a pipe spinning apparatus that having variable operational speeds, increasing safety in the operation of the spinning apparatus and reducing wear on the spinner and the associated threaded couplings.
It is a further object of the present invention to provide a spinning apparatus that requires less air flow for operation than the prior art spinning apparatus.
It is a still further object of the present invention to provide a spinning apparatus reduces the need for lubricators and water traps in the pneumatic system for operation.
It is still further object of the present invention to provide a spinning apparatus having a bearing system that increases the longevity of spinner and reduces wear on the associated equipment relative to the prior art spinners.
Accordingly, a pipe spinning apparatus connected in a drilling string for threadably connecting or disconnecting joints of pipes is provided. The pipe spinning apparatus includes a rotatable stem for connecting and disconnecting members, at least one pneumatic, turbine motor rotatably connected to the stem and a throttle control functionally connected to the turbine motor for variably controlling the speed of rotation of the stem. The rotational speed of the stem can be controlled through a range of revolutions per minute (rpm) depending on the air pressure and flow rate provided. The speed may be varied from 0 rpms to at least 500 rpms. A desirable range of operation is from 0 to 200 rpms. This ability to control and vary the speed of the stem greatly increases the safe operation of present kelly spinner over the prior art kelly spinners.
The kelly spinner of the present invention reduces the need for a lubricator and water trap in the air supply system. These elements are replaced with a strainer to prevent the passage of large particles into the turbine motors.
The kelly spinner of the present invention may also include a novel bearing system. The present kelly spinner includes a full tapered roller bearing set in the top bearing carrier and a straight radial roller bearing in the bottom bearing carrier. This novel bearing arrangement gives stability to the kelly stem when the pipe is being torqued and reduces wear to the stem, labyrinth plates and bearings in comparison to the prior art kelly spinners.